It seems that all the books I read on sleep including Dr. Sears' Sleep Book and the No Cry Sleep Solution suggest that "sleep begets sleep" meaning good naps = good night time sleep. For us, it seems the opposite is true. If our 7 month old daughter sleeps 2-3 hours in the morning for her first nap and has 2 more hour-long naps, she has a rough night. If she has 3 1-hour naps, she has a much better night.

Are there any studies showing either of these to be true? What have been your experiences?

And, if good night-time sleep is our goal, should I wake our daughter after an hour or 90 minutes during her first nap?

In my experience, nothing written in any book is true of every person on the planet. Well, except that we all breath, eat, sleep, and eliminate waste from our bodies. When and how we do these things is as individual as our DNA, nothing so queer as folk, including very small folk.

Try waking your daughter up after an hour for a few days and see if it really is a trend, she's your baby, you know her best. If it works and she really is sleeping better at night, whoo-hoo!

Just be prepared for it to change at the drop of a hat, probably at the worst possible time.

(The sleep begets sleep worked on my oldest and youngest sons. My second son and my daughter would be up until midnight (or 2 a.m. in my daughters case) if left to nap as long as they wanted.)

+1 for being prepared to chop and change schedules. ( I have also observed that sleeping patterns could change rather drastically) I think my daughters moods were the best indicators for me regarding her sleep/nap requirements during the day.

I've kept a spreadsheet of my baby's sleep habits and other data for a couple of months. I ran a correlation between amount of daytime sleep and "nighttime sleep quality" (a metric i made up -- # nighttime sleep hours * (10 - wakeups) / 10), and I got a very slight negative correlation.